Abstract:

For enabling to prevent ill effects from being generated in the structures
of a reflection mirror, even if increasing an output energy from a light
source, thereby preventing ill influences from being exerted on the
driving condition thereof, a mirror drive controller unit 7 reads out
history data of the past, relating to temperature changes on a micro
mirror 1, from a first LUT holder unit 19. Upon basis of the read-out
history data of the past is presumed the temperature on the micro mirror
1 at the present time. The presumed temperature on the micro mirror 1 is
temperature P temp of the micro mirror 1 at the present time, and upon
that P temp are changed vibration (or oscillation) condition of the micro
mirror 1 in the horizontal (H) direction and vibration (or oscillation)
condition thereof in the vertical (V) direction.

Claims:

1. An image displaying apparatus, comprising:a reflection mirror, which is
configured to display an image on a projection object, upon receiving a
light irradiated from a light source thereon, to reflect it into a
predetermined direction;a reflection mirror vibrating mechanism, which is
configured to vibrate said reflection mirror into a predetermined
direction;a temperature presuming unit, which is configured to presume
temperature on said reflection mirror, depending on driving condition of
said light source; anda vibration condition adjusting unit, which is
configured to adjust condition of the vibration of said reflection mirror
by said reflection mirror vibrating mechanism, to be corresponding to the
temperature on said reflection mirror, which is presumed within said
temperature presuming unit.

2. The image displaying apparatus, as is described in the claim 1, wherein
said reflection mirror vibrating mechanism comprises:a first vibration
mechanism, which is configured to vibrate said reflection mirror in a
first axial direction; anda second vibration mechanism, which is
configured to vibrate said reflection mirror in a second axial direction,
perpendicular to said first axial direction.

3. The image displaying apparatus, as is described in the claim 1, wherein
said temperature presuming unit presumes the temperature on said
reflection mirror, upon basis of accumulated value data of a light amount
irradiated from said light source, per every predetermined time-period.

4. The image displaying apparatus, as is described in the claim 3, wherein
said vibration condition adjusting unit adjusts vibration amplitude,
vibration frequency, or vibration phase of said reflection mirror by said
reflection mirror vibrating mechanism, to be corresponding to the
temperature on said reflection mirror, which is presumed within said
temperature presuming unit.

5. The image displaying apparatus, as is described in the claim 4, wherein
the adjustment upon the vibration condition of said reflection mirror,
which is conducted by said vibration condition adjusting unit, is
conducted such that a locus of the light reflected through said
reflection mirror on said projection object is in conformity with an
ideal condition of the locus of said light on said projection object.

6. An image displaying apparatus, comprising:a reflection mirror, which is
configured to display an image on a projection object, upon receiving a
light irradiated from a light source thereon, to reflect it into a
predetermined direction;a reflection mirror vibrating mechanism, which is
configured to vibrate said reflection mirror into a predetermined
direction;a photo detector unit, which is configured to output a
predetermined electric signal, after detecting a light incident upon said
projection object through said reflection mirror;a vibration condition
detector unit, which is configured to detect a vibration condition of
said reflection mirror, upon basis of the electric signal outputted from
said photo detector unit; anda controller unit, which is configured to
control said reflection mirror vibrating mechanism, so as to bring the
vibration condition of said reflection mirror into a desired vibration
condition, upon basis of the vibration condition of said reflection
mirror, which is detected by said vibration condition detector unit.

7. The image displaying apparatus, as described in the claim 6, wherein
said vibration condition detect or unit detects vibration amplitude,
vibration frequency, or vibration phase of said reflection mirror, which
are obtained by measuring a distance between the electric signals
outputted from said photo detector unit.

8. The image displaying apparatus, as described in the claim 6, wherein
said photo detector unit comprises:a photo transmitting member, which is
disposed in said projection object and is configured to transmit a light
incident thereupon; anda photo/electric converter element, which is
configured to input the light transmitted through said photo transmitting
member, so as to output a predetermined electric signal therefrom.

9. The image displaying apparatus, as described in the claim 6, wherein
said photo detector units are disposed within said projection object, in
plural number of sets thereof.

11. A method for adjusting vibration condition of a reflection mirror,
within an image displaying apparatus, having:a reflection mirror, which
is configured to display an image on a projection object, upon receiving
a light irradiated from a light source thereon, to reflect it into a
predetermined direction; anda reflection mirror vibrating mechanism,
which is configured to vibrate said reflection mirror into a
predetermined direction, comprising the following steps of:a first step
for presuming temperature on said reflection mirror, responding on
driving condition of said light source; anda second step for adjusting
vibration condition of said reflection mirror by said reflection
vibration mechanism, so as to fit the temperature on said reflection
mirror, which is presumed in said first step.

Description:

BACKGROUND OF THE INVENTION

[0001]1. Field of the Invention

[0002]The present invention relates to an image displaying apparatus,
comprising therein a reflection mirror for displaying an object to be
projected by receiving and reflecting a light irradiated from a light
source into a predetermined direction, and a method for adjusting
vibrating condition of the reflection mirror in the image displaying
apparatus.

[0003]2. Related Art

[0004]In recent years are tried applications of technologies, such as,
MEMS (Micro Electro Mechanical System) and a semiconductor laser
technology, into household electric appliances. As an example of that can
be listed up an application into an image displaying apparatus, for
drawing an image thereon, with using a laser light made of wavelength
components of visible lights, as a light source thereof (for example, see
the following Non-Patent Document 1). Also, within an image displaying
apparatus, comprising therein MEMS resonance mirrors is made a proposal
of generating an image through raster scanning of a laser light, by means
of that MEMS resonance mirrors, for a purpose of equalizing the
brightness of the image projected on a screen. In that proposal, when
conducting a laser scanning while outputting each pixel image data of
three (3) primary colors, R, G and B, an adjustment is made on the
intensity or strength of emission of the laser light depending upon speed
change of the raster scanning in the horizontal direction, thereby
obtaining an even or uniform brightness on the screen at each of bright
spots (for example, see the following Non-Patent Document 1).

[0007]By the way, with the image displaying apparatus comprising therein
the MEMS resonance mirrors, being pivotally supported so as to swing,
freely, into the vertical direction and the horizontal direction, it is
possible to achieve an increase of color reproduction region and/or a
high brightness, with a relatively low cost and with ease, in particular,
upon the image formed on the screen, by projecting the laser beam lights
emitted from the light source and reflected upon the MEMS resonance
mirrors. This is due to the fact that, accompanying an advancement of the
semiconductor laser technology in recent years, it is possible to achieve
an increase of output energy from the laser light source and/or an
increase of an efficiency in electric/photo conversion, and that it is
also possible to achieve an increase in selectivity of oscillation
wavelengths within the visible lights.

[0008]However, in general, the reflectivity of the laser beam lights upon
the reflection mirror (i.e., the MEMS resonance mirrors) is 90% or more
or less than that, approximately, within a range of the visible light
wavelengths, and components of the remaining 10% of the laser beam
lights, which are not reflected upon, are absorbed in the MEMS resonance
mirrors, and almost of them are converted into heats on the MEMS
resonance mirrors. For this reason, if increasing the output energy from
the laser light source, in order to achieve the high brightness of an
image or picture projected on the screen, then an amount of heats on the
MEMS resonance mirrors is increased, thereby rising up temperature of the
MEMS resonance mirrors; i.e., due to this, there is a possibility of
generating various ill effects on the structures of the MEMS resonance
mirrors. In addition to that mentioned above, there is also a possibility
of bringing about an ill influence upon swinging condition of the MEMS
resonance mirrors, which are pivotally supported so as to swing, freely,
into the vertical direction and the horizontal direction. Therefore, with
the conventional image displaying apparatus, actually, it is impossible
to achieve the high brightness of the projection image formed on the
screen, by increasing the output energy from the laser light source.

[0009]Accordingly, an object of the present invention is to provide an
image displaying apparatus, comprising there in reflection mirrors, which
can vibrate in one (1) axial direction or two (2) axial directions,
wherein the structures of reflection mirrors thereof can be protected
from being affected with ill influences applied thereupon, even if
increasing the output energy from the light source for achieving the high
brightness of the projection image.

[0010]An image displaying apparatus, provided according to a first aspect
of the present invention, comprises: a reflection mirror, which is
configured to display an image on a projection object, upon receiving a
light irradiated from a light source thereon, to reflect it into a
predetermined direction; a reflection mirror vibrating mechanism, which
is configured to vibrate said reflection mirror into a predetermined
direction; a temperature presuming unit, which is configured to presume
temperature on said reflection mirror, depending on driving condition of
said light source; and a vibration condition adjusting unit, which is
configured to adjust condition of the vibration of said reflection mirror
by said reflection mirror vibrating mechanism, to be corresponding to the
temperature on said reflection mirror, which is presumed within said
temperature presuming unit.

[0011]According to a preferable embodiment of the present invention,
according to the first aspect thereof, said reflection mirror vibrating
mechanism comprises: a first vibration mechanism, which is configured to
vibrate said reflection mirror in a first axial direction; and a second
vibration mechanism, which is configured to vibrate said reflection
mirror in a second axial direction, perpendicular to said first axial
direction.

[0012]According to other embodiment differing from the above, said
temperature presuming unit presumes the temperature on said reflection
mirror, upon basis of accumulated value data of a light amount irradiated
from said light source, per every predetermined time-period.

[0013]Also, according to other embodiment differing from the above, said
vibration condition adjusting unit adjusts vibration amplitude, vibration
frequency, or vibration phase of said reflection mirror by said
reflection mirror vibrating mechanism, to be corresponding to the
temperature on said reflection mirror, which is presumed within said
temperature presuming unit, appropriately.

[0014]Further, according to other embodiment differing from the above, the
adjustment upon the vibration condition of said reflection mirror, which
is conducted by said vibration condition adjusting unit, is conducted
such that a locus of the light reflected through said reflection mirror
on said projection object is in conformity with an ideal condition of the
locus of said light on said projection object.

[0015]An image displaying apparatus, provided according to a second aspect
of the present invention, comprises: a reflection mirror, which is
configured to display an image on a projection object, upon receiving a
light irradiated from a light source thereon, to reflect it into a
predetermined direction; a reflection mirror vibrating mechanism, which
is configured to vibrate said reflection mirror into a predetermined
direction; a photo detector unit, which is configured to output a
predetermined electric signal, after detecting a light incident upon said
projection object through said reflection mirror; a vibration condition
detector unit, which is configured to detect a vibration condition of
said reflection mirror, upon basis of the electric signal outputted from
said photo detector unit; and a controller unit, which is configured to
control said reflection mirror vibrating mechanism, so as to bring the
vibration condition of said reflection mirror into a desired vibration
condition, upon basis of the vibration condition of said reflection
mirror, which is detected by said vibration condition detector unit.

[0016]According to a preferable embodiment of the second aspect of the
present invention, said vibration condition detector unit detects
vibration amplitude, vibration frequency, or vibration phase of said
reflection mirror, which are obtained by measuring a distance between the
electric signals outputted from said photo detector unit.

[0017]Also, according to other embodiment differing from the above, said
photo detector unit comprises: a photo transmitting member, which is
disposed in said projection object and is configured to transmit a light
incident thereupon; and a photo/electric converter element, which is
configured to input the light transmitted through said photo transmitting
member, so as to output a predetermined electric signal therefrom.

[0018]Also, according to other embodiment differing from the above, said
photo detector units are disposed within said projection object, in
plural number of sets thereof.

[0019]Further, according to other embodiment differing from the above,
said light source includes therein: a red color light source for
irradiating a red color light towards said reflection mirror; a green
color light source for irradiating a green color light towards said
reflection mirror; and a blue color light source for irradiating a blue
color light towards said reflection mirror.

[0020]Further, according to a method for adjusting vibration condition of
a reflection mirror, within an image displaying apparatus, having: a
reflection mirror, which is configured to display an image on a
projection object, upon receiving a light irradiated from a light source
thereon, to reflect it into a predetermined direction; and a reflection
mirror vibrating mechanism, which is configured to vibrate said
reflection mirror into a predetermined direction, comprises the following
steps of: a first step for presuming temperature on said reflection
mirror, responding on driving condition of said light source; and a
second step for adjusting vibration condition of said reflection mirror
by said reflection vibration mechanism, so as to fit the temperature on
said reflection mirror, which is presumed in said first step.

[0021]According to the present invention, within the image displaying
apparatus comprising the reflection mirror vibrating in a first axial
direction and a second axial direction, even when increasing an output
energy from the light source, so as to obtain high brightness of the
projection image, it is possible to prevent ill effects from being
generated in the structures of the reflection mirror due to that, and
therefore it is possible to prevent ill influences from being extorted
upon the driving condition of the reflection mirror.

BRIEF DESCRIPTION OF THE DRAWINGS

[0022]Those and other objects, features and advantages of the present
invention will become more readily apparent from the following detailed
description when taken in conjunction with the accompanying drawings
wherein:

[0023]FIG. 1 is a function block diagram for showing the entire structures
of an image displaying apparatus, according to a first embodiment of the
present invention;

[0024]FIGS. 2(a) to 2(1) are explanatory views for showing a manner of
raster scanning, which is conducted within the image displaying apparatus
described in FIG. 1 mentioned above;

[0025]FIG. 3 is a function block diagram for showing the entire structures
of an image displaying apparatus, according to a second embodiment of the
present invention;

[0026]FIG. 4 is a function block diagram for showing the entire structures
of an image displaying apparatus, according to a third embodiment of the
present invention;

[0027]FIG. 5 is an explanatory view for showing an example of the
structures of a light receiving member shown in FIG. 4;

[0028]FIG. 6 is a function block diagram for showing the entire structures
of an image displaying apparatus, according to a fourth embodiment of the
present invention;

[0029]FIGS. 7(a) to 7(o) are timing chart for showing the operation of
each of portions building up the image displaying apparatus shown in FIG.
6;

[0030]FIG. 8 is a function block diagram for showing the entire structures
of an image displaying apparatus, according to a fifth embodiment of the
present invention; and

[0031]FIG. 9 is a function block diagram for showing the inner structures
of a light source driver portion, being included in each of an R video
signal converter portion, a G video signal converter portion and a B
video signal converter portion, respectively, which are shown in FIG. 8.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0032]Hereinafter, embodiments according to the present invention will be
fully explained by referring to the attached drawings.

[0033]FIG. 1 is a function block diagram for showing the entire structures
of an image displaying apparatus, according to a first embodiment of the
present invention.

[0035]The address generator unit 23 generates a write-in address signal
(hereinafter, being described as "W add") to the RAM 21 upon basis of a
horizontal synchronization signal (hereinafter, being described as "H
sync") inputted from a first input terminal 25 and a vertical
synchronization signal (hereinafter, being described as "V sync")
inputted from a second input terminal 27. The address generator unit 23
outputs the W add generated therein into the RAM 21, so as to designate a
memorizing position for a video signal (hereinafter, being described as
"video") inputted into the RAM 21 from a third input terminal 29, within
the RAM 21. With this, the video mentioned above can be stored into the
memory location within the RAM 21, which is designated by the W add.

[0036]The address generator unit 23 further inputs therein a horizontal
direction vibration reference signal (hereinafter, being described as "H
start"), i.e., a reference signal for vibration (oscillation) of the
micro mirror 1 in the horizontal direction, which is outputted from the
mirror drive controller unit 7. The address generator unit 23 also
generates a vertical direction vibration reference signal (hereinafter,
being described as "V start"), i.e., a reference signal for vibration
(or, oscillation) of the micro mirror 1 in the vertical direction, upon
basis of the H start mentioned above, so as to output that V start to the
mirror drive controller unit 7. In this case, it is also possible to
synchronize the timing for generating the V start with the timing of
inputting the V sync from the second input terminal 27 to the address
generator unit 23. The address generator unit 23, in synchronism with the
inputting timing of the H start and the generating/outputting timing of
the V start, generates a display position (i.e., coordinates); in other
words, a laser diode address signal (hereinafter, being described as "LD
Address") indicative of a specific pixel of video information during a
raster scanning (actually, it can be defined by a specific time within a
time period when the raster scanning is conducted). And, it outputs that
LD Address to the light source drive controller unit 13.

[0037]This LD Address is a signal, being necessary for drive (ON/OFF)
timing of a semiconductor laser, e.g., the light source 9, and for the
drive timing of the micro mirror 1; thus, for controlling the vibration
(or, oscillation) timing in the horizontal direction and the vibration
(or, oscillation) timing in the vertical direction. With this LD Address,
driving (ON/OFF) of the light source (e.g., the semiconductor laser) 9 is
controlled through the light source drive controller unit 13 and the
light source driver unit 15, and also through the mirror drive controller
unit 7 and the mirror driver unit 5, the vibration (or, oscillation) in
the horizontal direction and the vibration (or, oscillation) in the
vertical direction of the micro mirror 1 can be controlled. In other
words, through the raster scanning conducted through the ON/OFF drive of
the light source 9 and the vibrations in two (2) axial directions of the
micro mirror 1, a projection image or picture in relation to original
image information can be formed on a screen. And, within that projection
image, a brightness is adjusted at the position (e.g., the pixel) on the
plane coordinates (X,Y), corresponding to the LD Address mentioned above,
upon basis of a LD video outputted from the RAM 21 by an R Address, which
will be explained later. LD Address, R Address and LD Address will be
mentioned later, in details thereof.

[0038]The address generator unit 23 generates the R Address, as well as,
generation of the LD Address mentioned above, in synchronism with the
timing for inputting the H start and the timing for generating/outputting
the V start. That R Address is an address signal for reading out the
video stored in the Address (e.g., the memory location) corresponding to
the LD Address within the RAM 21. That R Address is outputted from the
address generator unit 23 into the RAM 21.

[0039]The RAM 21 inputs the video from the third input terminal and the W
Address from the address generator unit 23. And, it stored that video at
the memory location corresponding to the W Address, within the RAM 21.
The RAM 21, while inputting the R Address from the address generator unit
23, also outputs the video, which is stored at the memory location
corresponding to that R Address, to the light source drive controller
unit 13, as the LD video mentioned above, i.e., the signal for driving
the laser diode, or the light source 9.

[0040]The light source drive controller unit 13 inputs the LD Address from
the address generator unit 23 and the LD video from the RAM 21,
respectively. And, it obtains an amplification factor fitting to that LD
Address and amplifies that LD video by the amplification factor obtained;
thereby generating LD AMP, i.e., a signal for driving the laser diode, or
the light source 9, and it also outputs that LD AMP generated to the
light source driver unit 15.

[0041]The light source driver unit 15 drives the light source 9, upon
basis of the LD AMP mentioned above, which is outputted from the light
source drive controller unit 13. Thus, the light source driver unit 15
turns ON/OFF electricity supplies from an electric power source to the
light source 9, and in particular, when the supply of electricity is ON
from the electric power source to the light source 9, it supplies an
electric power, being amplified by the amplification factor based on the
LD AMP mentioned above, to the light source 9. The driving electric power
to be supplied with the light source 9 is adjusted in such a manner, by
the light source driver unit 15, that it is relatively small when
scanning on both end portions in the horizontal direction and in the
vicinity thereof or that it is relatively large when scanning at a
central portion in the horizontal direction and in the vicinity thereof,
during within the raster scanning. Also, during within the raster
scanning, the light source driver unit 15 adjusts the driving electric
power to be supplied with the light source 9, such that it becomes large
when scanning a pixel area or region of a relatively bright color, such
as, a white color or a warm color, for example, while it becomes small
when scanning a pixel area or region of a relatively dark color, such as,
a black color or a cold color, for example.

[0042]In the present embodiment, as the light source 9 is applied a laser
light source, which can irradiate a beam-like light and modulate an
amount of lights therefrom at high speed, easily. However, it is of
course that the light source 9, according to the present invention,
should not be restricted only to the laser light source. For example, in
the place of the laser light source may be applied any one of the
following light sources, such as, LED (light emitting diode), an
ultrahigh-pressure mercury lamp, a electrode-less lamp, etc., for
example, together with an optical part for condensing the lights
irradiated from that light source and/or a light modulator part of the
light amount. The light source 9, as was mentioned above, is turned
ON/OFF with the driving electric power supplied from the electric power
source to the light source 9, under the control of the light source drive
controller unit 13, and in particular, when the driving electric power is
ON, it is driven by the light source driver unit 15, which amplifies and
output that driving electric power in the manner mentioned above; i.e.,
produces a laser light and outputs it.

[0043]The beam light producer lens 11, upon receipt of the laser light
from the light source 9, produces a laser beam light, and it emits that
laser beam light towards the micro mirror.

[0044]The light amount integrator unit 17 obtains a total amount of light
emission of the laser light irradiated from the light source 9 towards
the beam light producer lens 11, within a predetermined reference
time-period. For example, if reproducing the video information for 60
frames during one (1) second (within the reference time-period), as the
projection image on the screen by the raster scanning, then the light
amount integrator unit 17 accumulates or integrates the electric energy
for each frame, which is supplied from the electric power source to the
light source through the light source driver unit 15, until elapsing one
(1) second, i.e., completing the raster scanning for 60 frames. From this
integrated value of the driving electric power can be calculated the
total amount of light emission of the light source 9. Within the
integrated value data mentioned above is the data of driving electric
power amount per a pixel, i.e., data of light emission amount. When
obtaining the data of integrated value about the light emission amount,
the light amount integrator unit 17 produces a histogram of that light
emission amount (i.e., data of integrated value of the driving electric
power), and outputs that histogram to the first LUT holder unit 19.

[0045]The first LUT holder unit 19 accumulates or integrates the
histograms, each of which is outputted from the light amount integrator
unit 17 every time when the predetermined reference time-period passes.
The histograms of the light emission amount per each the reference
time-period, which are accumulated within the first LUT holder unit 19,
build up history data of the past, indicating the manners, such as, what
is the temperature distribution on the micro mirror 1 and/or how the
temperature is changing on the micro mirror 1, for example. The first LUT
holder unit 19 outputs the above-mentioned past history data, which is
stored therein, to the mirror drive controller unit 7, responding to a
read-out request from that mirror drive controller unit 7.

[0046]The mirror drive controller unit 7, as well as, outputting the H
start mentioned above to the address generator unit 23, also inputs the V
start mentioned above, which is outputted from the address generator unit
23. The mirror drive controller unit 7, reading out the past history data
in relation to temperature changes of the micro mirror 1, which is stored
for each of predetermined reference time zones, from the first LUT holder
unit 19, also assumes or estimates, what will be the temperature of the
micro mirror 1 at the present of time, upon basis of the past history
data that is read out. And, it makes up the estimated temperature of the
micro mirror 1 to be the temperature P temp of the micro mirror at the
present time point.

[0047]Herein, since the temperature P temp of the micro mirror 1 is
affected or influenced by brightness/darkness of each pixel included in
each of the frames, then the temperature P temp mentioned above links
with the change of the above-mentioned LD video to be outputted from the
RAM 21 to the light source drive controller unit 13. This is because of
the fact that, depending upon a material building up the micro mirror 1,
a portion of the laser beam lights incident upon the micro mirror 1, not
being reflected thereon, but absorbed to turn into heats therein, and
depending upon the temperature characteristics of the material building
up this micro mirror 1, the vibration (or, oscillation) conditions of the
micro mirror 1 are changed, in the horizontal direction and the vertical
direction.

[0048]The mirror drive controller unit 7 selects H Freq, H AMP and H
phase, which are most suitable for obtaining the P temp mentioned above,
among plural numbers of vibration (or, oscillation) frequencies H freq,
plural numbers of vibration (or, oscillation) amplitudes H AMP, and
plural numbers of vibration (or, oscillation) phases H phas; i.e., the
predetermined vibration (or, oscillation) conditions in the horizontal
(H) direction, being necessary for setting up a value of temperature of
the micro mirror 1 at a predetermined value. At the same time of this,
upon basis of the H start and the V start mentioned above, the mirror
drive controller unit 7 selects V Freq, V AMP and V phase, which are most
suitable for obtaining the P temp mentioned above, among plural numbers
of vibration (or, oscillation) frequencies V freq, plural numbers of
vibration (or, oscillation) amplitudes V AMP, and plural numbers of
vibration (or, oscillation) phases V phas; i.e., the predetermined
vibration (or, oscillation) conditions in the vertical (V) direction,
being necessary for setting up a value of temperature of the micro mirror
1 at a predetermined value.

[0050]The mirror driver unit 5, when inputting those H Freq, H AMP, H
phas, V Freq, V AMP, and V phas mentioned above, from the mirror drive
controller unit 7, produces H drive and V drive upon those signals,
respectively; i.e., a mirror driving signal for vibrate (or, oscillate)
the micro mirror 1 in the horizontal (H) direction and a mirror driving
signal for vibrate (or, oscillate) the micro mirror 1 in the vertical (V)
direction. The mirror driver unit 5 outputs the mirror driving signals,
e.g., H drive and V drive, to the mirror driving/holding mechanism 3. The
mirror driving/holding mechanism 3 is made up with a horizontal (H)
direction driving/holding mechanism 3a, for holding the micro mirror 1 to
freely vibrate (or, oscillate) in the horizontal (H) direction, and a
vertical (V) direction driving/holding mechanism 3b, for holding the
micro mirror 1 to freely vibrate (or, oscillate) in the vertical (V)
direction. In such mirror driving/holding mechanism 3, a vibration speed
of the micro mirror 1 in the horizontal (H) direction, by means of the
horizontal (H) direction driving/holding mechanism 3a, is set at a value
larger than the vibration speed of the micro mirror 1 in the vertical (V)
direction, by means of the vertical (V) direction driving/holding
mechanism 3b. For this reason, after repeating the vibration of micro
mirror 1 in the H direction, a several number of times thereof, the
vibration thereof in the V direction is conducted only one (1) time.

[0051]For example, when displaying the image information corresponding to
(640 pixels×480 lines) of VGA (Video Graphics Array) at a renewal
speed of 60 Hz (i.e., displaying the video information for 60 frames
during one (1) second), within the image displaying apparatus shown in
FIG. 1, for example, there can be established the following relationship,
i.e., the vibration (or, oscillation) number of the micro mirror 1 in the
H direction is equal to 15 KHz or more than that, and the vibration (or,
oscillation) number thereof in the V direction is equal to 30 KHz or more
than that. In other words, during a half (1/2) cycle of the vibration
(or, oscillation) of the micro mirror 1 in the V direction, the vibration
(or, oscillation) of the micro mirror 1 occurs in the H direction occurs,
250 times or more than that. Hereinafter, explanation will be made, upon
assumption that the micro mirror 1 vibrates (or, oscillates) three (3)
times in the H direction, during when it vibrates (or, oscillates) only
one (1) time in the V direction, for easily understanding thereof.

[0052]Within the mirror driving/holding mechanism 3, when the H drive is
outputted from the mirror driver unit 5, the horizontal (H) direction
driving/holding mechanism 3a vibrates the micro mirror 1 in the
horizontal (H) direction, upon the H drive, and when the V drive is
outputted from the mirror driver unit 5, the vertical (V) direction
driving/holding mechanism 3b vibrates the micro mirror 1 in the vertical
(V) direction. Thus, the mirror driving/holding mechanism 3 holds the
micro mirror 1 to be vibrated in two (2) directions (i.e., the direction
of H axial and the direction of V axial), freely, corresponding to the H
drive and the V drive, which are outputted from the mirror driver unit 5.

[0053]The micro mirror 1 is made, mainly, of a material, such as, silicon,
for example, and as was mentioned previously, it is not able to reflect
all or the entire beam lights incident thereupon (i.e., the reflectivity
thereof is not 100%). Though a very little, for example, about 10% of the
beam lights incident thereupon are absorbed into the micro mirror 1, and
due to this fact the micro mirror generates heats therein. The micro
mirror 1 receives thereupon the laser lights from the light source 9,
which are condensed to be beam-like through the beam light producer lens
11, and is vibrated in the horizontal (H) direction by means of the
horizontal (H) direction driving/holding mechanism 3a and in the vertical
(V) direction by means of the vertical (V) direction driving/holding
mechanism 3b, respectively.

[0054]With this, the laser beam light reflected upon the micro mirror 1 is
irradiated upon a display area of the video information, which is shown
by a reference numeral on the screen, and thereby achieving the raster
scanning along a locus, as shown by a broken line 33. However, on an
axis, in parallel with a side of the display area 31 in the vertical
direction thereof, are plotted times tv (v0, v1, v2,
v3, v4, v5) relating to the vibration (or, oscillation) of
the micro mirror 1 in the vertical (V) direction, and on an axis, in
parallel with a side of the display area 31 in the horizontal direction
thereof, are plotted time th (h0, h1, h2, h3,
h4, h5), respectively. The locus 33 of raster scanning of the
laser beam light mentioned above, starting from a point positioning near
to an upper end of a center line h2 along with the vertical
direction within the above-mentioned display area 31, passes through an
intersecting point (tv,th)=(v0,h4) between a segment
v0, being in parallel with the axis th, and a segment h4,
being in parallel with the axis tv, and also through an intersecting
point (tv,th)=(v1,h0) between a segment v3,
being in parallel with the axis th, and a segment h0, being in
parallel with the axis th. And, the locus 33 of raster scanning also
passes through, an intersecting point (tv,th)=(v2,h4)
between a segment v2, being in parallel with the axis th, and a
segment h4, through an intersecting point
(tv,th)=(v3,h0) between a segment v3, in
parallel with the axis th, and a segment h0, and through an
intersecting point (tv,th)=(v4,h4) between a segment
v3, being in parallel with the axis th, and a segment h4,
too. And, further, the locus 33 of raster scanning also passes through an
intersecting point (tv,th)=(v5,h0) between a segment
v5, being in parallel with the axis th, and a segment h0,
and through an intersecting point between a side at a lower end of the
display area 31 and the center line h2, too.

[0055]Thus, in the raster scanning mentioned above, the vibration (or,
oscillation) of the micro mirror 1 generates three (3) times, in the H
direction, during a half cycle of the vibration (or, oscillation) of the
micro mirror 1 in the V direction thereof.

[0056]FIGS. 2(a) to 2(1) are explanatory views for showing the condition
of the raster scanning, which is conducted within the image displaying
apparatus described in FIG. 1.

[0057]In FIGS. 2(a) to 2(1), in particular, the condition 1 shown in FIG.
2(a) shows an ideal condition of the raster scanning, wherein the raster
scanning stars from a point positioning near to the upper end of the
center line h2, passing through the intersecting point
(tv,th)=(v0,h4), the intersecting point
(tv,th)=(v1,h0), the intersecting point
(tv,th)=(v2,h4), the intersecting point
(tv,th)=(v3,h0) the intersecting point
(tv,th)=(v4,h4) and the intersecting point
(tv,th)=(v5, h0), and reaches to the intersecting
point between the side at the lower end of the display area 31 and the
center line h2.

[0058]Under the condition that the driving (or, oscillating) condition for
each of the mirrors mentioned above is fixed, i.e., H AMP, H Freq, H
phas, V AMP, V Freq, and V phas, to be set up within the mirror drive
controller unit 7, an amount of the laser beam light to be incident upon
the micro mirror varies, and accompany with that, when the temperature P
temp of the micro mirror 1 is changed, there is generated a possibility
that the raster scanning cannot be carried out appropriately. Under the
condition 2 shown in FIG. 2(b), the locus 33 of the raster scanning does
not reach to the intersecting point (tv,th)=(v0,h4),
the intersecting point (tv,th)=(v2,h4) and the
intersecting point (tv,th)=(v4,h4), but it reaches
from the position near to the upper end of the center line h2, i.e.,
the starting point of the raster scanning, up to an intersecting point
between a side at the lower end of the display area 31 and the center
line h2. Also, under the condition 3 shown in FIG. 2(c), it does not
reach to even the intersecting point (tv,th)=(v1,h0),
the intersecting point (tv,th)=(v3,h0) and the
intersecting point (tv,th)=(v5,h0), further, in
addition to the respective intersecting points where it does not reach to
under the condition 2 shown in FIG. 2(b), but it reaches from the
position near to the upper end of the center line h2, i.e., the
starting point of the raster scanning, up to the intersecting point
between the side at the lower end of the display area 31 and the center
line h2.

[0059]Thus, either one of the condition 2 or the condition 3 indicates
that the amplitude of the vibration (or, oscillation) is short or
insufficient, in particular, in the horizontal (H) direction.

[0060]Next, under the condition 4 shown in FIG. 2(d), the locus 33 of the
raster scanning 33 reaches from the position near to the upper end of the
center line h2 up to the intersecting point between the side at the
lower end of the display area 31 and the center line h2, exceeding
the intersecting point (tv,th)=(v0,h4), the
intersecting point (tv,th)=(v1,h0), the intersecting
point (tv,th)=(v2,h4) the intersecting point
(tv,th)=(v3,h0), the intersecting point
(tv,th)=(v4,h4) and the intersecting point
(tv,th)=(v5,h0), greatly.

[0061]Thus, the condition 4 indicates that the amplitude of the vibration
(or, oscillation) is excessive, in particular, in the horizontal (H)
direction of the micro mirror 1.

[0062]Next, under the condition 5 shown in FIG. 2(e), the locus of the
raster scanning 33 goes beyond the intersecting point
(tv,th)=(v0,h4) and the intersecting point
(tv,th)=(v1,h0), greatly, where it would
intrinsically intersects with them, since the amplitude of the vibration
(or, oscillation) is excessive in the horizontal (H) direction of the
micro mirror 1, within a time region from the position near to the upper
end of the center line h2, i.e., the starting point of the raster
scanning, up to the position where it intersects with the section
v0, and also in a time region from the position where it intersects
with the section v0 up to when it intersects with the section
v1. Also, within a time region from the position where it intersects
with the section v4 to the position where it intersects with the
section v5, since the amplitude of the vibration (or, oscillation)
is short or insufficient in the horizontal (H) direction of the micro
mirror 1, the locus of the raster scanning 33 does not reach to the
intersecting point (tv,th)=(v4,h4) and the
intersecting point (tv,th)=(v5,h0), greatly, where it
would intrinsically intersects with them. The time region where the
amplitude of the vibration (or, oscillation) is appropriate in the value
thereof is only a time region from the position where the locus of the
raster scanning 33 intersects with the section v2 up to the position
where it intersects with the section v3.

[0063]Next, under the condition 6 shown in FIG. 2(f), the locus of the
raster scanning 33 does not reach to the intersecting point
(tv,th)=(v0,h4) and the intersecting point
(tv,th)=(v1,h0), greatly, where it would
intrinsically intersects with them, since the amplitude of the vibration
(or, oscillation) is short or insufficient in the horizontal (H)
direction of the micro mirror 1, within the time region from the position
near to the upper end of the center line h2, i.e., the starting
point of the raster scanning, up to the position where it intersects with
the section v0, and also in the time region from the position where
it intersects with the section v0 up to when it intersects with the
section v1. Also, within the time region from the position where it
intersects with the section v4 to the position where it intersects
with the section v5, since the amplitude of the vibration (or,
oscillation) is excessive in the horizontal (H) direction of the micro
mirror 1, the locus of the raster scanning 33 goes beyond to the
intersecting point (tv,th)=(v4,h4) and the
intersecting point (tv,th)=(v5,h0), greatly, where it
would intrinsically intersects with them. The time region where the
amplitude of the vibration (or, oscillation) is appropriate in the value
thereof is only a time region from the position where the locus of the
raster scanning 33 intersects with the section v2 up to the position
where it intersects with the section v3.

[0064]Therefore, in case where the locus 33 of the raster scanning is in
the condition 2 shown in FIG. 2(b) and the condition 3 shown in FIG.
2(c), the mirror drive controller unit 7 adjusts the H AMP, i.e., the
control signal for the vibration (or oscillation) amplitude, which is
outputted to the mirror driver unit 5, so as to increase the amplitude of
the vibration (or oscillation) in the horizontal (H) direction of the
micro mirror 1, thereby controlling it under the condition 1 shown in
FIG. 2(a). Also, in case where the locus 33 of the raster scanning is in
the condition 4 shown in FIG. 2(d), then the mirror drive controller unit
7 adjusts the H AMP, i.e., the control signal for the vibration (or
oscillation) amplitude, which is outputted to the mirror driver unit 5,
so as to reduce the amplitude of the vibration (or oscillation) in the
horizontal (H) direction of the micro mirror 1, thereby controlling it
under the condition 1 shown in FIG. 2(a).

[0065]Further, in the case where the locus 33 of the raster scanning is in
the condition 5 shown in FIG. 2(e) and the condition 6 shown in FIG.
2(f), the mirror drive controller unit 7 adjusts the H AMP, i.e., the
control signal for the vibration (or oscillation) amplitude, which is
outputted to the mirror driver unit 5, so as to increase or reduce the
amplitude of the vibration (or oscillation) in the horizontal (H)
direction of the micro mirror 1, appropriately, and thereby controlling
it under the condition 1 shown in FIG. 2(a).

[0066]However, the mirror drive controller unit 7 may adjust the H Freq,
i.e., the control signal for the vibration (or oscillation) frequency, in
the place of the control signal for the vibration (or oscillation)
amplitude, so as to obtain increasing/decreasing of the amplitude of the
vibration (or oscillation) in the horizontal (H) direction of the micro
mirror 1. Irrespective of conduction of increasing/decreasing the
amplitude of the vibration (or oscillation) in the horizontal (H)
direction of the micro mirror 1 by the variable adjustment of H AMP or
the adjustment of H Freq, however an adjustment is made upon the control
signal, V phas for the vibration (or oscillation) phase, in synchronism
with those adjustments, so as to produce the vibration reference signal
of horizontal direction mentioned above, i.e., H start, and thereby a
laser light is irradiated from the light source 9, upon basis of a drover
signal for the light source 9 fitting to that amplitude, i.e., LD video,
while controlling the amplitude of vibration (or oscillation) in the
horizontal (H) direction of the micro mirror 1, to be constant.

[0067]However, the case of the condition 7 shown in FIG. 2(g) shows that
it is under the ideal condition of the raster scanning, similar to the
case of the condition 1 shown in FIG. 2(a), and the case of the condition
8 shown in FIG. 2(h) shows that the amplitude of vibration (or
oscillation) of the micro mirror 1 is short or insufficient in the
vertical (V) direction. Next, the case of the condition 9 shown in FIG.
2(i) shows that the amplitude of vibration (or oscillation) is excessive
in the vertical (V) direction, and the case of the condition 10 shown in
FIG. 2(j) shows that the locus 33 of the raster scanning comes to be long
in the cycle of a sine wave, as it goes down in the figure. Next, the
case of the condition 11 shown in FIG. 2(k) shows that, on the contrary
to the case of the condition 10 shown in FIG. 2(j), the locus 33 of the
raster scanning comes to be short in the cycle of the sine wave, as it
goes down in the figure.

[0068]Further, the case of the condition 12 shown in FIG. 2(l) shows the
condition of combining the condition, which is similar to the condition 6
shown in FIG. 2(f), and the condition, which is similar to the condition
11 shown in FIG. 2(k), wherein the amplitude of vibration (or
oscillation) of the micro mirror 1 changes both, in the horizontal (H)
direction and also in the vertical (V) direction.

[0069]As was explained in the above, according to the first embodiment of
the present invention, in case where there is an interrelation or
correlation between the temperature of the micro mirror 1 and the
amplitude of the vibration (or oscillation) in the horizontal (H)
direction, which the micro mirror 1 can take, the locus 33 of the raster
scanning is controlled, so as to be in the condition 1 shown in FIG.
2(a), through adjusting the H AMP or H Freq, such that the temperature of
the micro mirror 1 comes to be a preset value of temperature while
determining the temperature of the micro mirror 1 upon basis of ant
amount of the laser beam emitted from the light source 9, and thereby
enabling the projection display within the display area or region on the
screen, with stability.

[0070]Within the first embodiment of the present invention mentioned
above, although optimization is made upon the driving (oscillating)
condition of the micro mirror (i.e., H AMP, H Freq, H phas, VAMP, V Freq
and V phas), which is determined by the mirror drive controller unit 7,
depending upon the temperature of the micro mirror 1, however driving of
the micro mirror 1 may be also stabilized, through controlling the
temperature of the micro mirror 1, by cooling down the micro mirror 1,
compulsively. Or, without adjusting the H AMP and the H Freq, it may be
also treated with, for example, changing the phase of staring the
radiation of the laser beam light upon basis LD video.

[0071]However, a turbulence is generated in the synchronization, when
adjusting the H Freq while fixing the V Freq, but it is also possible to
obtain the synchronization between the vibration in the vertical (V)
direction and the vibration in the horizontal (H) direction, i.e.,
stopping the vibration (or oscillation) in the horizontal (H) direction,
in the vibration (or oscillation) in the vertical (V) direction, during
the time when the vibration (or oscillation) direction is reversed, and
starting the vibration in the horizontal (H) direction, again, in
synchronism with the timing when staring the vibration (or oscillation)
in the vertical (V) direction. Further, upon adjusting the H Freq, H AMP
and H phas, while conducting the raster scanning, when the time is
different when it passes through each of the pixels, then it is also
possible to increase/decrease the intensity of the laser light outputted
from the light source 9, so as to bring an accumulated or integrated
amount of the lights for each of the pixels to be constant.

[0072]FIG. 3 is a function block diagram for showing the entire structures
of the image displaying apparatus, according to a second embodiment of
the present invention.

[0073]The image displaying apparatus shown in FIG. 3 differs from the
image displaying apparatus (e.g., according to the first embodiment of
the present invention) shown in FIG. 1, in the structures thereof, in
particular, in the following aspects: i.e., removing the light amount
integrator unit 17 and the first LUT holder unit 19 from the structures
shown in FIG. 1, and also adding a temperature detector unit 35, a
detected temperature value integrator unit 37, and a second lookup table
holder unit (hereinafter, being described as "second LUT holder unit")
39. However, with the structures shown in FIG. 3, but other than those
are same to those shown in FIG. 1, and therefore will be omitted the
explanation about the details thereof.

[0074]In FIG. 3, the temperature detector unit 35 is disposed in vicinity
of the micro mirror 1, and it detects the temperature of the micro mirror
1, so as to output an electric signal depending on the value of
temperature detected, to the detected temperature value integrator unit
37. The detected temperature value integrator unit 37, inputting the
temperature detection signal outputted from the temperature detector unit
35, obtains accumulated value data of the temperature value of the micro
mirror 1 during a reference time-period, which is determined in advance.
For example, if assuming that the video information for 60 frames are
reproduced through the raster scanning, as the projection image on the
screen, during 1 second (within the reference time-period), for example,
then the detected temperature value integrator unit 37 accumulates the
temperature value detected for each frame, which is outputted from the
temperature detector unit 35, until when it completes the raster scanning
for 60 frames, after elapsing 1 second.

[0075]Within this accumulated data of detected temperature values is
included a temperature value detected for each of the pixels included in
each of the frames. When obtaining the accumulated data of detected
temperature values, the detected temperature value integrator unit 37
produces a histogram of that accumulate data, and outputs that histogram
to the second LUT holder unit 39.

[0076]The second LUT holder unit 39 stores therein the histograms of the
accumulated data mentioned above, each of which is outputted from the
detected temperature value integrator unit 37 each time when passing the
predetermined reference time-period. The histograms of the accumulated
data for each reference time-period, which are stored within the second
LUT holder unit 39, function as the history data of the past indicative
of a manner of temperature distribution on the micro mirror 1 or a manner
of changing of temperature on the micro mirror 1. The second LUT holder
unit 39 outputs the history data of the past, which are stored therein,
to the mirror drive controller unit 7, responding to a request lo for
reading out the data made from that mirror drive controller unit 7.
Further, the mirror drive controller unit 7 determines the driving (or
oscillating) condition for the micro mirror 1, as was mentioned above, in
accordance with the processing steps, being similar to those within the
first embodiment of the present invention shown in FIG. 1.

[0077]Therefore, also within the present embodiment, it is possible to
control the locus 33 of the raster scanning, by the vibration (or
oscillation) of the micro mirror 1, so that it approaches to the ideal
condition of the raster scanning shown in FIG. 2(a).

[0078]As was mentioned above, according to the second embodiment of the
present invention, as well as, detecting the change of temperature on the
micro mirror 1, accurately, it is also possible to determine the driving
(or oscillating) condition suitable to the detected change of temperature
on the micro mirror 1, thereby to drive (or oscillate) the micro mirror 1
under a stable condition of obtaining an equal vibration frequency or an
equal vibration amplitude or an equal vibration phase.

[0079]FIG. 4 is a function block diagram for showing the entire structures
of the image displaying apparatus, according to a third embodiment of the
present invention.

[0080]The image displaying apparatus shown in FIG. 4 differs from the
image displaying apparatus (e.g., according to the first embodiment of
the present invention) shown in FIG. 1, in particular, by newly adding a
photo receiving member 41, a photo/eclectic converter element 43 and a
condition detector portion 45, in the structures thereof. However, since
the structures shown in FIG. 4, but other than those mentioned above, are
same to those shown in FIG. 1, and therefore in this FIG. 4, the same
reference numerals are attached for those shown in FIG. 1, but the
explanation will be omitted about the details thereof.

[0081]In FIG. 4, the photo receiving member 41 is a line-like member. This
photo receiving member 41 is disposed along the axis tv in FIG. 4,
at a position at one of the ends of the vibration (or oscillation) in the
horizontal (H) direction in the case where the locus 33 of the raster
scanning is in the ideal condition (i.e., the condition like that shown
in FIG. 2(b)), i.e., at least a part of an area or region, upon which the
lights reflected on the micro mirror 1 can radiate (or project) upon, but
not interrupting or obstructing them. Also, as was mentioned above, the
axis tv indicates the direction of the vibration (or oscillation) of
the micro mirror 1 in the vertical (V) direction. The photo receiving
member 41, receiving the reflection lights from the micro mirror 1,
reflects that reflection light received thereupon, or refracts them, into
a specific direction. The photo receiving member 41 will be mentioned in
more details thereof, later.

[0082]The photo/eclectic converter element 43 is provided at a position
for receiving the lights, which are reflected or refracted from the photo
receiving member 41. The photo/eclectic converter element 43 receives the
lights, which are reflected or refracted from the photo receiving member
41, at timing when the vibration (or oscillation) in the horizontal (H)
direction mentioned above intersects with the position where the photo
receiving member 41 is disposed as shown in FIG. 4, on the locus 33 of
the raster scanning. And, due to the lights received is generated
electromotive force, and with that electromotive force, a predetermined
electric signal PD1 is outputted to the condition detector portion 45. In
other words, the photo/eclectic converter element 43 outputs the electric
signal PD1 mentioned above, intermittently, at the timing when the
above-mentioned vibration (or oscillation) in the horizontal (H)
direction intersects the photo receiving member 41.

[0084]The comparator unit 47 inputs the above signal LD out, which is
outputted from the condition detector portion 45, and the signal LD
address mentioned above, which is outputted from the address generator
unit 23. As was mentioned previously, the signal outputted from the
address generator unit 23 is the signal, being necessary for controlling
the driving (ON/OFF) timing of the semiconductor laser, a being the light
source 9, and the timing for driving the micro mirror 1, e.g., the
vibration (oscillation) timing in the horizontal direction and the
vibration (oscillation) timing in the vertical direction thereof. From
that signal LD Address, it is possible to detect the drive (or oscillate)
condition, being appropriate for the micro mirror 1, i.e., H Freq, H AMP
and H phas.

[0085]The comparator unit 47 compares the above signal LD out and the LD
Address, and outputs the result of that comparison to the mirror drive
controller unit 7. The mirror drive controller unit 7 adjusts the drive
(or oscillate) condition of the micro mirror 1, e.g., H Freq, H AMP and H
phas, V Freq, V AMP and V phas, to be outputted to the mirror driver unit
5, again, upon basis of the comparison result mentioned above, which is
outputted from the comparator unit 47.

[0086]FIG. 5 is a view for showing an example of the structures of the
photo receiving member 41 shown in FIG. 4.

[0087]As is shown in FIG. 5, the photo receiving member 41 is made from an
optical fiber having an about rectangular parallelepiped (or,
parallelopipedon) configuration, as a whole thereof. Thus, the photo
receiving member 41 has a half-mirror construction, i.e., including a
light receiving surface, for receiving the lights thereon reflected on
the micro mirror 1, which is in a plane-like and rectangular
configuration thereof, and also a light transmission/diffusion body in an
inside thereof, and a mirror surface.

[0088]However, upon the fact that the locus 33 of the raster scanning
mentioned above passes through the photo receiving member 41, in addition
to H AMP, H Freq and H phas, indicating the vibration (or oscillation)
condition in the horizontal (H) direction, the condition detector portion
45 also obtains V AMP, V Freq and V phas, indicating the vibration (or
oscillation) condition in the vertical (V) direction, as the vibration
(or oscillation) frequency data, the vibration (or oscillation) amplitude
data and the vibration (or oscillation) phase data, indicating the
operating condition of the micro mirror 1, through the photo receiving
member 41 and the photo/eclectic converter element 43.

[0089]As was explained in the above, according to the third embodiment of
the present invention, with adjusting the vibration (or oscillation)
condition of the micro mirror 1, in such a manner that the timing, when
the lights reflected upon the micro mirror 1 (i.e., the locus 33 of the
raster scanning) intersects the photo receiving member 41, comes into an
appropriate vibration (or oscillation) frequency, an appropriate
vibration (or oscillation) amplitude and an appropriate vibration (or
oscillation) phase, it is possible to drive (or oscillate) the micro
mirror 1, with stability, under the driving (or oscillating) condition
suitable to the temperature of the micro mirror 1.

[0090]Also, even in case where the locus 33 of the raster scanning
mentioned above moves along a longitudinal direction of the photo
receiving member 41 while changing the vibration (or oscillation)
direction on the photo receiving member 41, since the condition detector
portion 45 can detect the change of that vibration (or oscillation)
through the photo receiving member 41 and the photo/eclectic converter
element 43, there is no necessity of providing that photo/eclectic
converter element 43, respectively, at plural numbers of places on the
photo receiving member 41, where the vibration (or oscillation) direction
can be changed on the locus 33 of the raster scanning, and therefore it
is possible to achieve reduction of costs of the parts thereof, easily.

[0091]With the third embodiment of the present invention, though the
explanation was explained so that the photo receiving member 41 is
disposed at least in a part of the area where the reflection lights from
the micro mirror 1 can be irradiated (or projected), however, it is of
course that the manner of disposition of the photo receiving member 41
should not be limited to that manner mentioned above. Even when the
position of disposing the photo receiving member 41 is disposed outside
the display area or region 31, but there is no problem if the photo
receiving element 41 is disposed in such the manner that the detection
result can be obtained, same or similar to that obtained in the manner
mentioned above.

[0092]FIG. 6 is a function block diagram for showing the entire structures
of the image displaying apparatus, according to a fourth embodiment of
the present invention.

[0093]The image displaying apparatus shown in FIG. 6 differs from the
image displaying apparatus shown in FIG. 4, in the structures thereof, in
particular, in the following aspects; i.e., the photo receiving member 41
and the photo/eclectic converter element 43, which are shown in FIG. 4,
are further disposed, in addition to the position where they are
disposed, as was shown in FIG. 4, also at the position, symmetrical with
that position about the center line h2 of the display area 31, and
that the condition detector portion 45 detects the operating condition of
the micro mirror 1, upon basis of the electric signal PD1, which is
outputted from the photo/eclectic converter element 43 shown at the
right-hand side in FIG. 6, and the electric signal PD2, which is
outputted from the photo/eclectic converter element 43 shown at the
left-hand side in FIG. 6. However, since the structures shown in FIG. 6,
but other than those mentioned above, are same to those shown in FIG. 4,
and therefore in this FIG. 6, the same reference numerals are attached
for those shown in FIG. 4, but the explanation will be omitted about the
details thereof.

[0094]In such the structures mentioned above, the condition detector
portion 45, as well as, measuring the distance between output timings of
the above-mentioned two (2) electric signals PD1 and PD2, each being
outputted, intermittently, from the photo/eclectic converter element 43
or 43, respectively, detects presence of the output of the electric
signal mentioned above, thereby obtaining the vibration (or oscillation)
frequency data, the vibration (or oscillation) amplitude data and the
vibration (or oscillation) phase data, indicating the operating condition
of the micro mirror 1, and it outputs the signal LD out, including the
vibration (or oscillation) frequency data, the vibration (or oscillation)
amplitude data and the vibration (or oscillation) phase data obtained in
the above, to the comparator unit 47. In the comparator unit 47 are
compared the signal LD out and the signal LD Address, so as to output the
comparison result thereof to the mirror drive controller. The processes
thereafter are almost same to those contents, which were explained by
referring to FIG. 4 in the above, and therefore the explanation thereof
will be omitted herein.

[0095]FIGS. 7(a) to 7(o) are timing charts for showing the operation of
each of portions building up the image displaying apparatus shown in FIG.
6 mentioned above.

[0097]Next, FIG. 7(d) shows a waveform of the vibration (or oscillation)
of the micro mirror 1 in the horizontal (H) direction when the locus 33
of the raster scanning is in the ideal condition, as is shown by the
condition 1 in FIG. 2(a), for example, and FIG. 7(e) shows a waveform of
the electric signal PD1, which is outputted from one of the
photo/eclectic converter elements 43 to the condition detector portion
45, when the locus 33 of the raster scanning is in the condition 1,
respectively. Next, FIG. 7(f) shows a waveform of the electric signal
PD2, which is outputted from the other of the photo/eclectic converter
elements 43 to the condition detector portion 45, when the locus 33 of
the raster scanning is in the condition 1, and FIG. 7(g) a waveform of
the LD out signal, which is outputted from the condition detector portion
45 to the comparator unit 47, when the locus 33 of the raster scanning is
in the condition 1, respectively.

[0098]Next, FIG. 7(h) shows a waveform of the vibration (or oscillation)
of the micro mirror 1 in the horizontal (H) direction when the locus 33
of the raster scanning is in the condition 2, which is shown in FIG.
2(b), for example, and FIG. 7(i) a waveform of the electric signal PD1,
which is outputted from one of the photo/eclectic converter elements 43
to the condition detector portion 45, when the locus 33 of the raster
scanning is in the condition 2, respectively. Next, FIG. 7(j) shows a
waveform of the electric signal PD2, which is outputted from the other of
the photo/eclectic converter elements 43 to the condition detector
portion 45, when the locus 33 of the raster scanning is in the condition
2, and FIG. 7(k) a waveform of the LD out signal, which is outputted from
the condition detector portion 45 to the comparator unit 47, when the
locus 33 of the raster scanning is in the condition 2, respectively.

[0099]Next, FIG. 7(l) shows a waveform of the vibration (or oscillation)
of the micro mirror 1 in the horizontal (H) direction when the locus 33
of the raster scanning is in the condition 3, which is shown in FIG.
2(c), for example, and FIG. 7(m) a waveform of the electric signal PD1,
which is outputted from one of the photo/eclectic converter elements 43
to the condition detector portion 45, when the locus 33 of the raster
scanning is in the condition 3, respectively. Next, FIG. 7(n) shows a
waveform of the electric signal PD2, which is outputted from the other of
the photo/eclectic converter elements 43 to the condition detector
portion 45, when the locus 33 of the raster scanning is in the condition
3, and FIG. 7(o) a waveform of the LD out signal, which is outputted from
the condition detector portion 45 to the comparator unit 47, when the
locus 33 of the raster scanning is in the condition 3, respectively.

[0100]As shown in FIG. 7(a) to 7(o), the H start signal is outputted one
by one, from the mirror drive controller unit 7 to the address generator
unit 23, at h0 when the vibration (or oscillation) of the locus 33
of the raster scanning reaches to one end of the display area 31 and
h4 when it reaches to the other end of the display area 31,
respectively. In other words, the H start signal is outputted from the
mirror drive controller unit 7 to the address generator unit 23, every
half cycle of the vibration (or oscillation) of the locus 33 of the
raster scanning in the horizontal (H) direction. In FIGS. 7(a) to 7(o),
the time-period from rise-up of the H start signal to rise-up of the next
coming H start signal is indicated by 1H.

[0101]The LD Address signal rises up after elapsing a constant time delay
from the rise-up of the H start signal. In FIGS. 7(a) to 7(o), where a
first LD Address signal rises up is at the position indicated by the time
h3, after the position indicated by the time h4where a first H
start signal rises up. Where this first LD Address signal falls down is
at the position, which is indicated by the time h1, after the time
h3. Next, where a second LD Address signal rises up is at the
position indicated by the time h1, after the position indicated by
the time h0 where a second H start signal rises up, and where this
second LD Address signal falls down is at the position indicated by the
time h3, after the time h1. Next, where a third LD Address
signal rises up is at the position indicated by the time h3, after
the position indicated by the time h4 where a third H start signal
rises up, and where this third LD Address signal falls down is at the
position indicated by the time h1, after the time h3.

[0102]Next, where a fourth LD Address signal rises up is at the position
indicated by the time h1, after the position indicated by the time
ho where a fourth H start signal rises up, and where this fourth LD
Address signal falls down is at the position indicated by the time
h3, after the time h1. Further, where a fifth LD Address signal
rises up is at the position indicated by the time h3, after the
position indicated by the time h4 where a fifth H start signal rises
up. The H drive signal is a sine-wave signal, taking the time between the
rise-up of the first H start signal and the rise-up of the third H start
signal or the time between the rise-up of the third H start signal and
the rise-up of the fifth H start signal, as one cycle, respectively.

[0103]The waveform of the vibration (or oscillation) of the micro mirror 1
in the horizontal (H) direction shown in FIG. 7(d), as is apparent from
that figure, can be also shown by the sine-wave, similar to the H drive
signal, and the cycle thereof is also almost same to the cycle of the H
drive signal. The waveform of the vibration (or oscillation) in the
horizontal (H) direction is shifted from the H drive signal in the phase,
i.e., from the time h2, to the time h4. In FIG. 7(e), a first
PD1 signal rises up at the time h1 where the first LD Address signal
rises up, and a second PD1 signal falls down at the time h1 where
the second LD Address signal rises up. A third PD1 signal rises up at the
time h1 where the third LD Address signal falls down, and a fourth
PD1 signal falls down at the time h1 where the fourth LD Address
signal rises up.

[0104]In FIG. 7(f), a first PD2 signal falls down at the time h3
where the first LD Address signal rises up, and a second PD2 signal rises
up at the time h3 where the second LD Address signal falls down. A
third PD2 signal falls down at the time h3 where the third LD
Address signal rises up, and a fourth PD2 signal rises up at the time
h3 where the fourth LD Address signal falls down. A fifth PD2 signal
falls down at the time h3 where the fifth LD Address signal rises
up. In FIG. 7(g), a first LD out signal is in synchronism with the first
LD Address signal, a second LD out signal with the second LD Address
signal, a third LD out signal with the third LD Address signal, a fourth
LD out signal with the fourth LD Address signal, and a fifth LD out
signal with the fifth LD Address signal, respectively.

[0105]The waveform of the vibration (or oscillation) of the micro mirror 1
in the horizontal (H) direction shown in FIG. 7(h) is also in the
sine-wave, being similar to the wave of the micro mirror 1 in the
horizontal (H) direction shown in FIG. 7(d); however, the maximum value
in the amplitude thereof is a little bit smaller than that of the
waveform of the vibration (or oscillation) shown in FIG. 7(d). Regarding
the phase, it is almost same to that of the waveform of the vibration (or
oscillation) shown in FIG. 7(d). Regarding the PD1 signals, any one of
them rises up at the time ho, and also regarding the PD2 signals, at the
time h4. Further, regarding the LD out signals, the first, third and
fifth ones rise up at the time h4, and fall down at the time
h0, respectively, while the second and forth LD out signals rise up
at the time h4, and fall down at the time h0, respectively.

[0106]And, the waveform of the vibration (or oscillation) of the micro
mirror 1 in the horizontal (H) direction shown in FIG. 7(l) is also the
sine-wave, being similar to the wave of the micro mirror 1 in the
horizontal (H) direction shown in FIGS. 7(d) and 7(h); however, the
maximum value in the amplitude thereof is considerably smaller than that
of the waveform of the vibration (or oscillation) shown in FIG. 7(d).
Regarding the phase, it is almost same to that of the waveform of the
vibration (or oscillation) shown in FIGS. 7(d) and 7(h). Regarding the
PD1 signals, PD2 signals, and LD out signals, any one of them is not
outputted.

[0107]As was explained in the above, according to the fourth embodiment of
the present invention, it is possible to adjust the driving (or
oscillating) condition of the micro mirror, so as to bring it into the
vibration (or oscillation) frequency, the vibration (or oscillation)
amplitude and the vibration (or oscillation) phase, being appropriate
much more, comparing to the third embodiment of the present invention
mentioned above, and thereby enabling to drive (or oscillate) the micro
mirror 1, with stability, while determining or setting up the driving (or
oscillating) condition of the micro mirror 1 to be high in the accuracy
thereof.

[0108]FIG. 8 is a function block diagram for showing the entire structures
of the image displaying apparatus, according to a fifth embodiment of the
present invention.

[0109]The image displaying apparatus shown in FIG. 6 differs from the
image displaying apparatus shown in FIG. 4, in the structures thereof, in
particular, in an aspect that, in addition to the light source shown by
the reference numeral 9 and the beam light producer lens shown by the
reference numeral 11 in FIG. 4, there are further provided the
followings; i.e., a light source, which is shown by a reference numeral
57, a beam light producer lens, which is shown by a reference numeral 59,
a light source, which is shown by a reference numeral 61, a beam light
producer lens, which is shown by a reference numeral 63. In FIG. 8, the
light source 9 functions as the light source for irradiating a laser
light of blue color (B), and the beam light producer lens 11, receiving
the laser light of the blue (B) color irradiated from the light source 9
thereupon, produces a laser beam light of the blue color; i.e., being
used as the beam light producer lens, for emitting that blue color laser
beam directing onto the micro mirror 1. Also, the light source 57
functions as the light source for irradiating a laser light of green
color (G), and the beam light producer lens 59, receiving the laser light
of the green (G) color irradiated from the light source 57 thereupon,
produces a laser beam light of the green color; i.e., being used as the
beam light producer lens, for emitting that green color laser beam
directing onto the micro mirror 1. Further, the light source 61 functions
as the light source for irradiating a laser light of red color (R), and
the beam light producer lens 63, receiving the laser light of the red (R)
color irradiated from the light source 61 thereupon, produces a laser
beam light of the red color; i.e., being used as the beam light producer
lens, for emitting that red color laser beam directing onto the micro
mirror 1.

[0110]Also, in the image displaying apparatus shown in FIG. 8 are provided
three (3) sets of video signal converter units, i.e., a R (red color)
video signal converter unit 51, a G (green color) video signal converter
unit 53 and a B (blue color) video signal converter unit 55,
corresponding to the three (3) light sources 9, 57 and 61, respectively.
Those video signal converter units 51, 53 and 55 are same in the
structures thereof, and each includes the light source drive controller
unit 13, the light source driver unit 15, the light amount integrator
unit 17, and the first LUT holder unit 19, which are shown in FIG. 4.
Since each unit of those was already mentioned, previously, in the
details thereof, duplication of explanation thereof will be omitted. In
this FIG. 8, the R video signal converter unit 51 controls the driving of
the light source 61 (i.e., irradiating the red color laser light), the G
video signal converter unit 53 the driving of the light source 57 (i.e.,
irradiating the green color laser light), and the B video signal
converter unit 55 the driving of the light source 9 (i.e., irradiating
the blue color laser light), respectively. However, since the structures
shown herein, but other than those mentioned above, are same to those
shown in FIG. 4, and therefore in this FIG. 8, the same reference
numerals are attached for those shown in FIG. 4, but the explanation will
be omitted about the details thereof.

[0111]In the structures mentioned above, the R video signal converter unit
51 inputs the LD Address from the address generator unit 23, and a kind
of the LD video from the RAM 21, i.e., R video, respectively. That R
video includes therein bright/dark information relating to a red color
(R) video signal (i.e., information indicating brightness for each pixel
in relation with the red color (R) video signal). The R video signal
converter unit 51 obtains an amplification factor fitting to the LD
Address, so as to amplify the R video at that amplification factor
obtained, and thereby producing the LD AMP, i.e., the signal for driving
the light source 61, and at the same time, it also drives the light
source 61 with that LD AMP produced. With this, the light amount of the
red color laser light irradiated from the light source 61 can be
modulated. The G video signal converter unit 53, similar to that within
the R video signal converter unit 51, also inputs the LD Address from the
address generator unit 23, and G video, respectively. That G video
includes therein bright/dark information relating to a green color (G)
video signal (i.e., information indicating brightness for each pixel in
relation with the green color (G) video signal). The G video signal
converter unit 53 obtains an amplification factor fitting to the LD
Address, so as to amplify the G video at that amplification factor
obtained, and thereby producing the LD AMP, i.e., the signal for driving
the light source 57, and at the same time, it also drives the light
source 61 with that LD AMP produced. With this, the light amount of the
green color laser light irradiated from the light source 57 can be
modulated. Also, the B video signal converter unit 55, similar to that
within the G video signal converter unit 53 and/or the R video signal
converter unit 51, inputs the LD Address from the address generator unit
23, and B video, respectively. That B video includes therein bright/dark
information relating to the blue color (B) video signal (i.e.,
information indicating brightness for each pixel in relation with the
blue color (B) video signal). The B video signal converter unit 55
obtains an amplification factor fitting to the LD Address, so as to
amplify the B video at that amplification factor obtained, and thereby
producing the LD AMP, i.e., the signal for driving the light source 9,
and at the same time, it also drives the light source 9 with that LD AMP
produced. With this, the light amount of the blue color laser light
irradiated from the light source 9 can be modulated.

[0112]The R video signal converter unit 51, the G video signal converter
unit 53, or the B video signal converter unit 55, in parallel with the
processing operation mentioned above, produces and stores therein,
respectively, a histogram of an amount of light emission per a unit of a
reference time, i.e., the history data of the past, for showing a manner
of the temperature distribution on the micro mirror 1 and/or a manner of
changes of the temperature on the micro mirror 1. And, it outputs the
above-mentioned history data of the past stored therein to the mirror
drive controller unit 7, responding to the request of data readout from
the mirror drive controller unit 7. The mirror drive controller unit 7
presumes what the temperature is on the micro mirror 1 at the present
time, upon basis of the history data, and sets that temperature of the
micro mirror 1 presumed, as the temperature P temp on the micro mirror 1
at the present time. The following steps of processing are as mentioned
previously.

[0113]FIG. 9 is a function block diagram for showing the internal
structures of the light source driver unit 15 (shown in FIG. 1, FIG. 3,
FIG. 4 and FIG. 6), which is included in any one of the R video signal
converter unit 51, the G video signal converter unit 53 and the B video
signal converter unit 55 shown in FIG. 8.

[0114]The light source driver unit 15 mentioned above comprises therein,
as shown in FIG. 9, four (4) sets of PWM (i.e., Pulse Width Modulation)
circuit 67, 69, 71 and 73, four (4) sets of pulse amplifier circuits 75,
77, 79 and 81, and an adder 83. Inputs of those PWM circuits 67, 69, 71
and 73 are connected with the output terminal 65 of the light source
drive controller unit 13 (shown in FIG. 1, FIG. 3, FIG. 4 and FIG. 6),
respectively. Thus, any one of the four (4) sets of PWM circuits 67, 69,
71 and 73 is connected with the output terminal 65 of the light source
drive controller unit 13, in parallel with one another. The pulse
amplifier circuit 75 is connected with an output of the PWM circuit 67,
the pulse amplifier circuit 77 with an output of the PWM circuit 69, the
pulse amplifier circuit 79 is connected with an output of the PWM circuit
71, and the pulse amplifier circuit 81 with an output of the PWM circuit
73, respectively. An input of the adder 83 is connected with outputs of
the pulse amplifier circuits 75, 77, 79 and 81.

[0115]The PWM circuits 67, 69, 71 and 73 input two (2) bits of the signal
PL AMP of eight (8) bits, by each, which is inputted from the light
source drive controller unit 13 through the output terminal 65, and treat
pulse width modulation on the above-mentioned two (2) bits signal
inputted, upon basis of the bright/dark information for each pixel of the
original video data, which is indicated by each of the two (2) bits
signal inputted. (Thus, an adjustments is made upon ON-time widths of the
inputted signal LD AMP (i.e., the pulse signal), indicating the
time-period of displaying one (1) pixel within the video data to be
displayed on the display area 31 (i.e., the time widths of light
emissions of the light sources (9, 57 and 61)).) With this, on the
display area 31 mentioned previously, a projection image of the original
video data is displayed, the brightness of which is ranked within the
region of 256 gradations for each pixel.

[0116]The pulse amplifier circuits 75, 77, 79 and 81 input the two (2)
bits signals (i.e., the pulse signals), after being adjusted upon the
ON-time width thereof, which are outputted from the corresponding PWM
circuits 67, 69, 71 and 73, respectively, and amplify waveforms of the
ON-time width of those two (2) bits signals (i.e., the pulse signals).
And, they output the signals after that (pulse) amplification, to the
adder 83, respectively.

[0117]The adder 83 adds the (pulse) signals after being treated with the
pulse amplification, which are outputted from the pulse amplifier
circuits 75, 77, 79 and 81, respectively. With this, a light source
driver signals is produced, which indicates a specific one gradation
within the 256 gradations, for a certain pixel within the original video
data. The adder 83 outputs that light source driver signal to the light
sources (9, 57 and 61).

[0118]As was explained in the above, according to the fifth embodiment of
the present invention, even if increasing the output energy from the
light source (i.e., the light emission amount from the light source), for
achieving the high brightness of the projection image, it is possible to
bring the irradiation timings of the laser lights from the light sources
(9, 57 and 59), for displaying the projection image on the display area
31, to be synchronized with the oscillations of the micro mirror 1 in the
horizontal (H) direction and the vertical (V) direction, by means of the
mirror driving/holding mechanism 3, at high accuracy, and thereby
enabling prevention of ill effects from generating within the structures
of the micro mirror 1, also prevention of ill influences from being
exerted upon the driving (or oscillating) condition of the micro mirror
1, and further enabling the video or image display with stability.

[0119]Also, upon basis of the electric signal PD1 outputted from the
photo/eclectic converter elements 43, intermittently, the position on the
display area 31 is determined, corresponding to the time-period from
starting display of the projection image until finishing the display
thereof on the display area 31, every time when the micro mirror 1
oscillates in the horizontal (H) direction and the vertical (V)
direction, and with this, the display position of the projection image
can be fixed on the display area 31, even under the condition where the
oscillation of the micro mirror 1 changes in width thereof, and therefore
it is possible to reproduce the original video data under a stable
condition.

[0120]Also, when displaying the original video data on the display area
31, under the condition of oscillating the micro mirror 1 in the
horizontal (H) direction and the vertical (V) direction, it is possible
to adjust the intensity of the laser lights to be irradiated from the
light sources (9, 57 and 61), in a step-like manner, thereby enabling to
achieve bright/dark gradation display with high accuracy. Also, adding
the signals, which are outputted from the plural number of pulse
amplifier circuits (75, 77, 79 and 81), respectively, within the adder
83, enables to increase the number of gradations, with ease, for the
purpose of enabling to express the degree of brightness/darkness for each
of pixels building up the original video data, finely, without increasing
processing speed within the circuit operations. Further, by determining
an overlap of the laser beam light between the pixels themselves,
neighboring to each other in the oscillation direction of the micro
mirror 1, for each of the gradations, it is also possible to conduct a
control on definitions (i.e., an extension of a pixel) for each of the
pixels, with ease.

[0121]While we have shown and described several embodiments in accordance
with our invention, it should be understood that disclosed embodiments
are susceptible of changes and modifications without departing from the
scope of the invention. Therefore, we do not intend to be bound by the
details shown and described herein but intend to cover all such changes
and modifications that fall within the ambit of the appended claims.